Lecture 11

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Comments for Lecture 11

"Adhesive luting of indirect restorations." American Journal of Dentistry. 13:60D-76D, 2000 Nov. This review highlighted some of the ideal characteristics of luting agents used for indirect restorations. The article recommends resin cements as the best material due to superior material properties and wear behavior. Also, the ultrasonic insertion technique is advised when using relatively viscous cements. Good fit of the restoration and radiopacity of cement were noted as important factors for controlling overhang. Finally, the author states that the viscosity and filler content of the resin cement do not affect the wear properties within the marginal luting area.
Scott Stadsklev <stad0040@umn.edu>
- Friday, October 15, 2004 at 10:02:27 (CDT)

After our lecture on cementing and luting in restorative dentistry I found the following article of interest. Kato H. Matsumura H. Tanaka T. Atsuta M. Bond strength and durability of porcelain bonding systems. [Journal Article] Journal of Prosthetic Dentistry. 75(2):163-8, 1996 Feb. This article looked at durability and bond strength of various bonding systems to feldspathic porcelain. The investigators used different combinations of primers and luting agents to test the shear bond strengths. Their results showed that a reduction in bond strengths were present in all of the systems they investigated after thermocyling (a device to measure shear bond strengths).
Karrie Powell <powe0033@umn.edu>
- Friday, October 15, 2004 at 08:32:09 (CDT)

I chose to research a paper relating to the luting of porcelain veneers, which was discussed by Dr. Perdigao in the last lecture. One article compared the plasma arc light (PAC) unit and the conventional halogen light to polymerize dual curing resin cement beneath porcelain laminate veneers. The PAC unit has been claimed to be more efficient in curing resin composites (a shorter curing time). Ten specimens were polymerized conventionally (40 seconds) and the other specimens by plasma arc curing (PAC) (6 seconds). These sections were subjected to microshear testing and the number of failures were recorded. The differences in bond strength between veneers cured with the different lights was statistically significant. Samples polymerized with halogen light showed better bond strength. The results of this study suggest that the PAC was less efficient in curing through porcelain at the suggested curing time than conventional halogen light polymerization. "The efficiency of different light sources to polymerize resin cement beneath porcelain laminate veneers" Journal of Oral Rehabilitation. 31(2):160-5, 2004 Feb.
Timothy J. Neuner <neun0004@umn.edu>
- Friday, October 15, 2004 at 06:53:58 (CDT)

This study examined the impact of thermocycling on the development of surface flaws on the cemented surfaces of PLV restorations prepared by acid-etching or alumina (Al2O3) abrasion. The veneer surfaces were either abraded with a disc or acid etched. Other specimens were coated with a resin luting cement prior to thermocycling to simulate the conditions encountered when the veneer is in use. The two-way ANOVA revealed significant differences between the mean strength values of the porcelain specimens abraded with 50 microm Al2O3 compared with the higher strength HF acid-etched specimens. Significant differences were also identified in the mean fracture strength data for the abraded cemented and acid-etched cemented groups with the abraded groups recording the highest strength levels. They concluded in this studey that composite resin polymerisation shrinkage may help to strengthen porcelain surfaces by imposing a compressive stress on the porcelain surface. However, the strength of the HF etched cemented groups when bonded to composite resin were weaker than abraded specimens. Etching the porcelain provides not only the necessary surface roughness conducive to mechanical interlocking, but would appear to have a weakening effect on the porcelain surfaces. Dent Mater. 2004 Mar;20(3):286-92.
sara palokangas <palo0030@umn.edu>
- Friday, October 15, 2004 at 06:45:40 (CDT)

I was interested in lerning more about phosphate monomer-based self-etch adhesive cements. In the “Comparative Study on Adhesive Performance of Functional Monomers” the adhesive interaction of 3 functional monomers with synthetic hydroxyapatite were chemically characterized, using x-ray photoelectron spectroscopy and atomic absorption spectrophotometry. Interaction with dentin was characterized ultra-morphologically, using transmission electron microscopy. The monomer 10- methacryloxydecyl dihydrogen phosphate (10-MDP) readily adhered to hydroxyapatite. This bond appeared very stable, as confirmed by the low dissolution rate of its calcium salt in water. The bonding potential of 4-methacryloxyethyl trimellitic acid (4-MET) was substantially lower. The monomer 2-methacryloxyethyl phenyl hydrogen phosphate (phenyl-P) and its bond to hydroxyapatite did not appear to be hydrolytically stable. Besides self-etching dentin, specific functional monomers have additional chemical bonding efficacy, as it may interact chemically with hydroxyapatite, that is expected to contribute to their adhesive potential to tooth tissue. Reference: Yoshida Y, Nagakane K, Fukuda R, Nakayama Y, Okazaki M, Shintani H, Inoue S, Tagawa Y, Suzuki K, De Munck J, Van Meerbeek B. “ Comparative study on adhesive performance of functional monomers”. J Dent Res. 2004 Jun;83(6):454-8
Melissa (Karter) Naidyhorski <kart0015@umn.edu>
- Friday, October 15, 2004 at 06:30:48 (CDT)

When compairing the luting cemnets in class I was wondering if if there was a difference in Ant va posterior cements used, comig from an esthic perspective. However the article I found looked at anterior luting cemnts in the anterior and compaired them in use with porcelin and composites. The prepartions were similar to what we discussed in class and the results show that luting cement was stronger for the porcelin than the composite. THe reason I brin gthis up is because I think it is crucial that the appropriate cements be used with the apporpriate materials to maximize the strength and durability of the resoration.Dental Materials. Mar;20(3):286-92 (2004.
David Mach <machx004@umn.edu>
- Friday, October 15, 2004 at 06:18:46 (CDT)

the keyword I chose was "luting cements". As noted in the lecture, luting cements are being widely used for composite, inlay and onlay restorations. The following study, "Radiopacity of posterior composite resins, composite resin luting cements, and glass ionomer lining cements", tested the various radiopacties of three different luting cements when used with different types of restorations. they found that different luting cements showed that when used with composites, the cements showed a varied radiopacity, usually of lower value when compared to the composite. They also concluded that when luting cements were combined with different restorative applications, that the lower radiopacity could interfere with the diagnosis of caries and the detection of gaps near the restoration. this article can be found in the journal of Prosthetic Dentistry. 1993 Oct;70(4):351-5.
joshua vang <vang0335@umn.edu>
- Friday, October 15, 2004 at 00:57:08 (CDT)

In the last lecture, Dr. Perdiago discussed the different types of cement use to lute porcelain to teeth. As for the different types of light cure cements, I was wondering if the type of curing light used made a difference in the bond strength. In a study performed by Rasetto and others found in the Journal of Prosthodontics, the efficiency of 3 different light sources used to polymerize a light curing resin cement beneath porcelain veneers were evaluated. The 3 different lights studied were a conventional halogen light, a plasma arc light, and a high intensity halogen light. A surface hardness test (Knoop indenter) was used on veneers cured with the different lights to determine the level of photopolymerization through the ceramic material with each of the light sources. The results of this study indicated that high intensity curing lights achieve adequate polymerization of resin cements through veneers in a markedly shorter time period than the conventional halogen light. Rasetto FH, Driscoll CF, von Fraunhofer JA. “Effect of light source and time on the polymerization of resin cement through ceramic veneers.” J Prosthodont. 2001 Sep;10(3):133-9.
Jared Homan <homa0023@umn.edu>
- Friday, October 15, 2004 at 00:04:46 (CDT)

I looked at a study that compared Ceromer resin and porcelain veneers. They looked at color, esthetics, and marginal adaptation. They found that at baseline, both veneer types showed good quality in all aspects, but at 12 months, the margins began breaking down. Furthermore, they found that working with Ceromer was more difficult to finish and had more marginal discoloration. They did however, conclude that veneers work well for esthetics. There are other types of veneers on the market. It would be interesting to see how they do under SEM at 12 months. "Clinical and scanning electron microscopic assessments of porcelain and ceromer resin veneers." Dhawan P, Prakash H, Shah N. Indian J Dent Res. 2003 Oct-Dec;14(4):264-78.
Dan Lunstad <lund0724@umn.edu>
- Thursday, October 14, 2004 at 22:51:39 (CDT)

In recent years, there has been considerable overlap between the concept of a resin cement and dentin/enamel bonding agents to yeild the "Universal Resin Adhesive" for multi-purpose bonding in dentistry. It would seem that Panavia is very versitile and has extremely good properties for cementation of crowns, bridges, endodontic posts, amalgam bonding/cavity base materials, and as a dentin bonding agent for composites. Porcelain Primers (Silane Bonding Agents) are also very good for porcelian cements as these agents actaully penetrate into the surface of the porcelain and creates a hybrid layer which is regarded as part resin and part porcelian. Shade selection is warrented before cementation of any veneer or all ceramic crown. Reference: "12. Dental Cements - 2. Resin Cements", Dental Material Science, Dr. Noel Ray, University Dental School and Hospital, Wilton, Cork, Ireland, Copyright 1998.
Jared Rediske <redi0028@umn.edu>
- Thursday, October 14, 2004 at 22:45:29 (CDT)

After lecture I wanted to learn more about the strength of porcelain veneers. They are becoming more and more popular with our increasing demand for esthetics. The study I read looked at the effect of occlusal veneer porcelain thickness on the load at fracture of Procera AllCeram crowns. To do this, dies were manufactured to incorporate the features of an all-ceramic crown preparation on a premolar tooth. They were then divided into five groups of varying thicknesses of porcelain, axially and occlusally. The crowns were cemented onto their respective dies with a resin luting agent. Specimens were placed in a universal testing machine with a controlled compressive load. It was found that increasing the thickness of the occlusal veneer porcelain increased the load at fracture for Procera AllCeram crowns. There was no significant difference in load at fracture between the Procera and In-Ceram crowns. Harrington Z, McDonald A, Knowles J. An invitro study to investigate the load of fracture of Procera AllCerm Crowns with various thickness of occlusal veneer porcelain. Int J of Prosthodontics. 16(1):54-8, 2003 Jan-Feb.
Michelle Olson <olso1984@umn.edu>
- Thursday, October 14, 2004 at 22:22:05 (CDT)

Tylka DF, Stewart GP. Comparison of acidulated phosphate fluoride gel and hydrofluoric acid etchants for porcelain-composite repair. J Prosthet Dent. 1994 Aug;72(2):121-7. In class Dr. Perdigo talked about porcelain etching and the use of hydrofluoric acid. He discussed the toxicity of this etchant and how careful one must be when using it. The study I looked at compared the hydorfluoric acid with acidulated phosphate fluoride gel, a much less dangerous etchant. The results of the study showed that neither of the etchants produced an acceptable bond strength with composite. With the tests run they concluded that the hydrofluoric acid is no more effective then the acidulated phosphate fluoride gel for use as a porcelain etchant.
Amber Cziok <czio0002@umn.edu>
- Thursday, October 14, 2004 at 22:21:07 (CDT)

In the last lecture the topic of ceramic cements was discussed. The article evaluated discussed specifically the type of cememt on the marginal adaptation of all-ceramic MOD inlays. The aim of this study was to investigate the in-vitro marginal adaptation of all-ceramic class II inlays, which were luted with conventional multi-stage pre-treatment cements and one new type of cement. The marginal integrity of each tooth was evaluated at cement-dentin and cement-enamel junctions, where each inlay was luted on human molars with two resin cements, one compomer, one resin modified glass-ionomer and one new resin cement. Dual curing modifications were investigated. It was found that in the resin cements and the new material the marginal integrity was higher than 90% before and after thermal cycling and mechanical loading. The marginal adaptation was between 55-80% for the resin modified glass-ionomer, and lower than 20% for the compomer. As for microleakage only compomer was lower than 20% for all cements. The significance is that the difference in marginal integrity between the new universal resin cement and conventional resin cements after total-etching, priming and bonding was not significant. This article seemed to have rather weak data, and a low muber of trial. In addition, the fact that this study was in vitro adds to its weakness. In my opinon, futher investigation is required to make these claims. Reference: Rosentritt M, Behr M, Lang R, Handel G."Influence of cement type on the marginal adaptation of all-ceramic MOD inlays." Dent Mater. 2004 Jun;20(5):463-9. Influence of cement type on the marginal adaptation of all-ceramic MOD inlays.
Andrew Pearson <pear0235@umn.edu>
- Thursday, October 14, 2004 at 21:53:52 (CDT)

I reviewed an article evaluating the shear bond strength of resin cements to both ceramic and dentin. They used 480 ceramic discs divided into 6 groups of 80 discs each. Each group received 6 different surface conditioning treatments before the application of resin cement. These surface treatments were sanding with 600-grit silicon carbide paper, microetching with aluminum oxide, sanding followed by silane application, microetching followed by silane application, hydrofluoric acid-etching, and hydrofluoric acid-etching followed by silane application. Each group then was subdivided into 4 subgroups for the application of 1 of 4 cements: Nexus, Panavia 21, RelyX ARC, and Calibra. Shear bond strength was evaluated at 24 hours and at 6 months. The HF acid etching followed by silane application demonstrated the highest bond strength for each of the 4 cements. The Journal of Prosthetic Dentistry Volume 88, Issue 3 , September 2002, Pages 277-284
Judy Schmidt <schm1244@umn.edu>
- Thursday, October 14, 2004 at 21:24:05 (CDT)

The paper I read tested the performance of both light-curing and dual-cured adhesive/luting systems (as control), when used in combination with translucent fibre posts. The results were evaluated by means of pull-out test and scanning electron microscopy (SEM ) observation. No statistically significant difference was found between the light-curing system group and the dual cured one. SEM observations showed a good bond between the dentin and the post whatever the curing method employed. However, a dual curing system seems to be the most appropriate method since it allows to cure even those areas which would not be otherwise reached by light. "Translucent fiber post cementation using a light-curing adhesive/composite system: SEM analysis and pull-out test." Giachetti L, Russo DS, Bertini F, Giuliani V. J Dent. 2004 Nov;32(8):629-34.
Paul Schaus <scha0764@umn.edu>
- Thursday, October 14, 2004 at 21:21:08 (CDT)

Cementation agents used for fixed prosthodontic restorations obtain adhesion to the tooth surface by a luting process, a chemical reaction, or micromechanical retention. This paper compared shear-bond strength of cementing agents to gold castings, Procera AllCeram, IPS Empress, and IPS Empress 2. The cementing agents tested included zinc phosphate (Fleck's zinc cement), glass-ionomer cement (FujiI, Ketac-Cem, RMGI (Fuji Plus, FujiCem, RelyX Luting), resin cement (RelyXARC, Panavia F, Compulute), and Self-adhesive universal resin (RelyX Unicem). The only cements that showed strong bond strength were the resin cements and the self-adhesive universal resin cements.
Rhonda Senjem <senj0007>
- Thursday, October 14, 2004 at 20:55:58 (CDT)

I found an interesting article that investigated how luting cements affect the properties of the porcelain material used to veneer anterior teeth. They prepared veneers by either HF etching or air abrading the interior surfaces, cemented them and then tested the porcelain for fracture strength. It seems that after luting them, the composite resin polymerisation shrinkage may help to strengthen porcelain surfaces by imposing a compressive stress on the porcelain surface. HOWEVER, the strength of the HF etched cemented groups when bonded to composite resin were WEAKER than abraded specimens. Etching the porcelain does not only provide the necessary surface roughness conducive to mechanical interlocking but would appear to have a weakening effect on the porcelain surfaces.Dent Mater. 2004 Mar;20(3):286-92.
Ben Selden <seld0013@umn.edu>
- Thursday, October 14, 2004 at 20:09:54 (CDT)

First, I was interested in the comment by Dr Pergigao about the inability of light to penetrate porcelain restoratations. I was curious as to the various factors that effect the limited ability of light to penetrate a restoration. In a study by Rasetto FH. Driscoll CF. Prestipino V. Masri R. von Fraunhofer JA. they look at different variables in light polymerization and found out that the depth of polyermerization depended on the thickness of the ceramic and the intensity of the light. The light from Halogen bulbs was deemed unable to produce stable results in various thickness of restorations. Clinical relevence is that Halogen bulbs may work for some applications but not for all. Journal of Prosthetic Dentistry. 91(5):441-6, 2004 May.
adm curtis <curt0119@umn.edu>
- Thursday, October 14, 2004 at 19:28:56 (CDT)

The research artical I read investigated the color properties and stability of paint-on resins used for clor modifications on veneer restorations. They used three different shades of the paint-on resin and the attempted to simulate wear on the restoration by replicating toothbrush abrasion, ultraviolet (UV) light irradiation, water imerssion and staining tests. They then measure these test against a previously investigated crown and bridge resin as a control. The was no significant change in color properties for the test except for the staining test. The results of this research showed that these paint-on resins were at least as stable as the crown and brige resins and far as color and optical properties go. Arikawa H. "Optical and color stabilities of paint-on resins for shade modification of restorative resins." Dental Materials Journal. 23(2):155-60, 2004 Jun.
Eric Scotland <scot0223@umn.edu>
- Thursday, October 14, 2004 at 19:11:32 (CDT)

The study I looked at examined color stability of veneers luted with three different types of luting agents; self-cure, dual cure, and light cure. 5 samples of each were prepared and subjected to an accelerated aging process for 900 hours. Measurements were made at intervals of 300, 600, and 900 hours. There were no significant differences in the amount of overall color change among the 3 resin cements at the same aging period. The dual-cure material showed the greatest chroma change at each aging time. The greatest hue change was determined for self-cure material. The light-cure resin cement tested can be proposed as a suitable material for luting laminate veneers, but other long-term studies prove this better. Hekimoglu C, Anil N, Etikan I. Effect of accelerated aging on the color stability of cemented laminate veneers. Int J Prosthodont. 2000 Jan-Feb;13(1):29-33.
Dan Connors <conn0295@umn.edu>
- Thursday, October 14, 2004 at 17:59:36 (CDT)

This study looked at the difference in the microleakage of laminate veneers with different incisal edge preparations. 1)window preparation with the preparation ending at the incisal edge, and 2)preparation extending to the lingual including the incisal edge. The cervical margins were the same on both groups, about 1mm incisal from the CEJ. The study found that the microleakage in both groups was about the same at the cervical margin. However, the window prep seemed to "prevent" microleakage better that did the other group. "A microleakage study of ceramic laminate veneers by autoradiography: effect of incisal edge preparation." Journal of Oral Rehabilitation. 31(3):265-9, 2004 Mar.
fiedler, jack <fied0017@umn.edu>
- Thursday, October 14, 2004 at 17:46:51 (CDT)

I chose an article with the title "Single-step, self-etch adhesives behave as permeable membranes after polymerization. Part I. Bond strength and morphologic evidence." The purpose of their study was to test the hypotheses that microtensile bond strengths of single-step, self-etch adhesives to hydrated dentin are adversely affected by delayed-activation of a light-cured composite, as well as the use of a chemical-cured composite. So, they took seven commercially available and one experimental single-step, self-etch adhesives and bonded them to hydrated human dentin. A dual-cured composite was used and activated using: [1] the light-cured mode (base paste only-control), [2] the chemical-cured mode (base and catalyst pastes, in the dark); and [3] delayed light-activation (base syringe only, left on top of cured adhesives in the dark for 20 minutes before activation). After microtensile bond strength evaluation, fractured samples were examined using SEM. Intact, unstressed interfaces of [1] and [3] were examined with TEM. Microtensile bond strengths were also evaluated for selected adhesives bonded to dehydrated dentin and coupled with the composite activated by [2] or [3]. The results that they obtained were that for all adhesives, bond strengths decreased significantly to bonded hydrated dentin when the composites were activated with [2] or [3] (P< 0.001). Whereas the hybrid layer-adhesive interface was intact, water-blisters that developed along the adhesive-composite interface in these two modes were responsible for the decline in bond strength. When bonded to dehydrated dentin, delayed light-activation of the light-cured composite did not result in compromised bond strength. The results of chemical-cured composites improved but were more variable and system-dependent. Their results seem good. It was a good article to read post-lecture about adhesives. Everything that they talked about I had a good grasp on. Reference:Am J Dent. 2004 Aug;17(4):271-8. Single-step, self-etch adhesives behave as permeable membranes after polymerization. Part I. Bond strength and morphologic evidence. Tay FR, Pashley DH, Suh B, Carvalho R, Miller M.
Joby Jaberi <jabe0002@umn.edu>
- Thursday, October 14, 2004 at 16:13:51 (CDT)

Is there a difference in the hardness and marginal adaptability and sealing between dual cure and chemical cure resin cements? el-Badrawy WA, el-Mowafy OM, Chemical versus dual curing of resin inlay cements., J Prosthet Dent. 1995 Jun;73(6):515-24 examined the degree of hardness between the dual cure resin cements and the chemical cure resin cements for placing inlays. These results concluded that ‘chemical curing alone was not sufficient to achieve maximum hardening.’ Where might chemical cure resin cements be indicated?
Atty Smith <smit1820>
- Thursday, October 14, 2004 at 16:09:40 (CDT)

The paper I chose studied the differences between two chemically cured composite bonding resins. They chose Sondhi Rapid Set (SD) and Maximum cure and used them in an indirect bonding technique. They found that both chemically cured adhesives were suitable for indirect bonding of brackets however the SD adhesive had seven times the number of breakages than the MC adhesive. Reference:Miles PG. Weyant RJ. A clinical comparison of two chemically-cured adhesives used for indirect bonding. [Clinical Trial. Controlled Clinical Trial. Journal Article] Journal of Orthodontics. 30(4):331-6; discussion 299, 2003 Dec.
Cory Larson <clarson5@umn.edu>
- Thursday, October 14, 2004 at 15:53:58 (CDT)

I read an article that talk about luting alumina reinforced porcelain to different resin luting agents. The article looked at four different luting agents and compared them by using two controls. One being water and the other being thermocycling. Most showed adhesive failure except three combination of luting agents and a silane coupling agent. Since this article was published in 2004 I would cosider use of the three agents that did not fail and see clinically how they worked for me. Nakamura S, Yoshida K, Kamada K, Atsuta M. Bonding between resin luting cement and glass infiltrated alumina-reinforced ceramics with silane coupling agent. J Oral Rehabil. 2004 Aug;31(8):785-9.
Ryan Dunlavey <dunl0060@umn.edu>
- Thursday, October 14, 2004 at 15:02:41 (CDT)

I chose a paper that looked at the effect of solvents on the bond strength of resin bonded porcelain. Clinical trials of porcelain veneers for chairside color modifications may require the use of a trial resin with various colors of tints. The bond strength effects of four different solvents used for removal of trial resin from etched porcelain specimens were investigated. Fifty-six porcelain specimens were fabricated, flattened by a metallurgically standard method, etched with hydrofluoric acid and silane treated. The specimens were divided into four groups at random. The trial resin material was cleaned with different solvents prior to bonding of a dual cure resin composite. After bonding the specimens were stored in water at 37 °C for 7 days. The results indicated that the resin–porcelain bond strengths were not affected by the type of solvent used to remove trial resin. This procedure is recommended for clinical cases when resin composite is used for the try-in of etched porcelain bonded restorations. Journal of Oral Rehabilitation; Nov99, Vol. 26 Issue 11, p853, 5p
Matt Hendrickson <hend0485@umn.edu>
- Thursday, October 14, 2004 at 14:28:40 (CDT)

I read an article on the long-term survival of porcelain veneers using two different preparation designs. The study looked at teeth that had incisal porcelain coverage and compared their 5,6, and 7 year survival on those that did not have incisal coverage. Of the 110 teeth they looked at, 6 of the 9 failures were in veneers without incisal coverage. This would seem to indicate that a slightly more aggressive preparation may have more long term benefits for the patient. Smales RJ, Etemadi S. "Long-term survival of porcelain laminate veneers using two preparation designs: a retrospective study." Int J Prosthodont. 2004 May-Jun;17(3):323-6.
Jeff Johnson <john2990@umn.edu>
- Thursday, October 14, 2004 at 14:24:16 (CDT)

Braga RR. Ferracane JL. Condon JR. Polymerization contraction stress in dual-cure cements and its effect on interfacial integrity of bonded inlays. Journal of Dentistry. 30(7-8):333-40, 2002 Sep-Nov.The researchers in this study wanted to test their hypothesis that dual-cure resin cements generate higher stress on contraction when they are light cured than when they are used as self cure resin cements. They believed that this stress would affect microleakage and cause gaps between the interfaces. They tested three dual cure resin cements: Calibra, Choice and RelyX ARC. They found that the stress caused in dual cure mode was higher than when the cements were used in a self-cure mode. In self-cure mode there were no differences between the two materials. Choice and RelyX ARC showed higher microleakage in dual-cure mode than in self-cure mode. Calibra didn't show a difference in microleakage between activation modes.
Nicole Little <littlej@umn.edu>
- Thursday, October 14, 2004 at 13:31:13 (CDT)

This paper studied the shear-bond strength of cementing agents to high-gold-content alloy castings and different dental ceramics. The cements tested were a zinc-phosphate cement (Fleck's zinc cement), glass ionomer cements (Fuji I, Ketac-Cem), resin-modified glass ionomer cements (Fuji Plus, Fuji Cem, RelyX Luting), resin cements (RelyX ARC, Panavia F, Variolink II, Compolute), and a self-adhesive universal resin cement (RelyX Unicem). None of the cement types provided the highest bonding values with all substrate types, so different cements are better for different retorations and only the self-adhesive universal resin cement (RelyX Unicem) and 2 of the resin cements (Panavia F and Compolute) exhibited strong bond strengths to specific prosthodontic materials. In contrast, zinc-phosphate, glass ionomer, and resin-modified glass ionomer cements showed the lowest values. In vitro shear bond strength of cementing agents to fixed prosthodontic restorative materials. Piwowarczyk A, Lauer HC, Sorensen JA. J Prosthet Dent. 2004 Sep;92(3):265-73.
Nick Lowe <Lowe0082@umn.edu>
- Thursday, October 14, 2004 at 13:30:01 (CDT)

This study compares the success/failure rate of pin retained and bonded amalgam restorations in large amalgam restorations involving at least the coverage of one cusp. After six years, the researchers evaluated the restorations. They found that there were no significant differences in failure rates, marginal adaptation, marginal discoloration, secondary caries, tooth sensitivity or tooth vitality. The bonded amalgams performed just as well in actual patients as did the pin retained amalgams. Summitt JB, Burgess JO, Berry TG, Robbins JW, Osborne JW, Haveman CW. "Six-year clinical evaluation of bonded and pin-retained complex amalgam restorations." Oper Dent. 2004 May-Jun;29(3):261-8.
Katie Sealey <maes0008@umn.edu>
- Thursday, October 14, 2004 at 12:42:45 (CDT)

The purpose of this study was to evaluate the microleakage characteristics of laminate veneers with different incisal edge preparation. There were two preparation types; The incisal finish line of 20 teeth was placed at the incisal edge (window type preparation) or The incisal finish line of the other 20 teeth was placed linguoincisally (incisal edge overlapped type preparation). In the two preparation types the cervical microleakages were of similar degree. The incisal microleakages in the overlapped laminate veneers were greater than in the window type veneers. In conclusion, the window preparation type was more effective in terms of prevention of microleakage at the incisal margin than the overlapped type laminates A microleakage study of ceramic laminate veneers by autoradiography: effect of incisal edge preparation. Journal of Oral Rehabilitation. 31(3):265-9, 2004 Mar
Mesa Ulwelling <ulwe0007>
- Thursday, October 14, 2004 at 12:40:40 (CDT)

In the article, "Comparison of the apical seal obtained by a dual-cure resin based cement or an epoxy resin sealer with or without the use of an acidic primer," the researchers compared four methods of sealing an endodontically treated tooth. Gutta Percha and Panvia F were used with and without the use of a primer and were tested for dye leakage. The results showed that Panvia F, a dual-cured resin cement, is not suitable for mantaining a seal. The study also showed that the use of a primer did not reduce the amount of dye leakage. Journal of endodontics [0099-2399] Britto yr: 2002 vol: 28 iss: 10 pg: 721
Jessica Johnson <johjessi@yahoo.com>
- Thursday, October 14, 2004 at 12:32:16 (CDT)

I read an article looking at different bonding systems in bonding all ceramic crowns. The testing was done in-vitro using CAD/CAM restorations placed on maxillary premolars looking at fracture load. The tests resulsts showed that the use of a primer, porcelain liner, was effective for treating the surface of all ceramic crowns before cementation. This is important since more people are concered with estheics and are requesting all porcelain restorations. With this the same type of quality needs to be done as with more traditional restorations. Reference: Attia A., Kern M. "Fracture strength of all-ceramic crowns luted using two bonding methods." Journal of Prosthetic Dentistry. 91(3):247-52, 2004 Mar.
David Maki <dmaki1@umn.edu>
- Thursday, October 14, 2004 at 12:23:31 (CDT)

The article I read studied resin-bonded ceramic restorations, and the temperature increase caused by different light curing units. The study found that curing units characterized by high-energy output caused the greatest increase in temperature, but that even this temperature increase wasn't high enough to reach critical levels for pulpal health. My question is: Does the chemical reaction in dual-cure resin cements cause a temperature change worth worrying about? Usumez A., Ozturk N. "Temperature increase during resin cement polymerization under a ceramic restoration: effect of type of curing unit." Int J Prosthodont. 2004 Mar-Apr;17(2):200-4.
Alicia Berger <berg1305@umn.edu>
- Thursday, October 14, 2004 at 11:06:23 (CDT)

I read an article from the Brazilian Dental Journal that evaluated shear bond strength of composite to porcelain. Although they were bonding porcelain to composite and not dentin, some of the techniques and materials used were the same/similar to those described by Dr. Perdigao. The article stated, "bond strength to porcelain was predominantly influenced by the type of conditioning agent rather than the type of luting agent." Surfaces were prepared using burs, sandblasting with aluminum-oxide or etching and silane agents. The gels used for etching were phosphoric and hydrofluoric acids. The study found that mechanical retention increased bond strength a little. Significant difference was found when the porcelain was conditioned with phosphoric or hydrofluoric acid. No significant difference was found between the two acids. The article also mentioned that hydrofluoric acid may not be necessary and should be substituted by phosphoric acid, due to it's chemically aggressive nature. The best results may be a combination of sandblasting with acids on porcelain silanization. Kussano, Claudia M., et al. Evaluation of Shear Bond Strength of Composite to Porcelain According to Surface Treatment. Brazilian Dental Journal 2003; 14(2): 132-135
Mickey Moua <moua0114@umn.edu>
- Thursday, October 14, 2004 at 10:46:58 (CDT)

Bonded amalgam can be a good option for very large amalgam restorations. Although the longevity of the bond is still up for debate, there has been an initial reduction in microleakage shown with bonded amalgam. This study showed no significant difference in the performance of resin based cement and resin-modified glass ionomer in the reduction of microleakage. Both showed a significant improvement over those with no adhesive system used Braz Dent J. 2004;15(1):13-8. Epub 2004 Aug 16.
Paul Kocian <koci0005@umn.edu>
- Thursday, October 14, 2004 at 10:46:56 (CDT)

The study I read explored a new method for repairing the dentition defect involving multiple teeth. Forty patients who had severe dentition defect were enrolled in this study. The defects were repaired by reserving the residual roots and the application of dowels and light-cure composite resin as the post-core of the long ceramic bridge. The patients were followed up for 2-4 years, and a success rate of 92.5% was achieved. Reserving the residual root, application of dowel and light-cure composite resin as the post-core of long ceramic bridge is effective for repairing severe dentition defect. (Dowel and composite resin as the post-core of long ceramic bridge for repair of dentition defect. DiYi Junyi Daxue Xuebao. 24(5):600-1, 2004 May)
rian suihkonen <suih0002@umn.edu>
- Thursday, October 14, 2004 at 10:43:14 (CDT)

Rasetto FH. Driscoll CF. von Fraunhofer JA.Effect of light source and time on the polymerization of resin cement through ceramic veneers. Journal of Prosthodontics. 10(3):133-9, 2001 Sep. In class on Wednesday we discussed the cementation process of porcelain veneers. Dr. Perdigo mentioned that in curing a cement underneath a porcelain veneer it may be wise to double the time normally recommended for that cement. However, he did not focus on what type of curing light is most appropriate. This article evaluated the efficiency of 3 different light sources to polymerize a light curing resin cement beneath 3 types of porcelain veneer materials. A conventional halogen light, a plasma arc light, and a high intensity halogen light were used to polymerize resin cement (Variolink II; Ivoclar North America Inc, Amherst, NY) through disks of veneer materials. Equal diameter and thickness disks of feldspathic porcelain, pressable ceramic, and aluminous porcelain were used as an interface between the curing light tips and the light polymerized resin cement. The resin cement/veneer combinations were exposed to 4 different photopolymerization time protocols of 5 seconds, 10 seconds, 15 seconds, and 20 seconds for high intensity light units and 20 seconds, 40 seconds, 60 seconds, and 80 seconds for conventional halogen light. Results showed that the hardness values of the cements vary with the light source, the veneer material, and the polymerization time. For a given light and veneer material, Knoop Hardness Number increases with longer polymerization times. High intensity curing lights achieve adequate polymerization of resin cements through veneers in a markedly shorter time period than the conventional halogen light. However, the data in this report indicate that a minimum exposure time of 15 seconds with the high intensity lights regardless of the composition of the veneer. Conventional halogen lights required a correspondingly greater polymerization time of 60 seconds. I am not even sure we use halogen lights anymore in clinics and I have not seen one on our clinic floor. Anyone know if we use them or not?
Marika Middag <midd0058@umn.edu>
- Thursday, October 14, 2004 at 10:20:36 (CDT)

The article that I found compared the strength of three different resin cements (Panavia 21, Noribond DC, and Variolink II) bonded to two different types of feldspathic porcelain (Noritake EX-3 and Ceramco). The surfaces of the porcelain were etched with hydrofluoric acid. The study was conducted in vitro, and the samples were thermal-cycled for 180 days. Shear bond strength was measured to the point of failure of the bond. The study found that there was no difference between the bonds to the two different porcelains, but that Panavia 21 was significantly weaker than the other two resin cements. (Blatz MB. Sadan A. Maltezos C. Blatz U. Mercante D. Burgess JO. In vitro durability of the resin bond to feldspathic ceramics. [Journal Article] American Journal of Dentistry. 17(3):169-72, 2004 Jun.)
Paul Amundson <amun0141@umn.edu>
- Thursday, October 14, 2004 at 10:16:28 (CDT)

In lecture on Wed, Dr. Perdigao talked about different cements and luting them to porcelain veneers. He also descibed the process of using HF acid etch for the porcelain surface. I found an article that talked about using HF acid or AlO abrasion as a means of increasing surface area. Based on their study they found positives for both technique, but in the end stated that HF acid overall weakens the porcelain whereas the aluminum oxide abrasion has an enhanced bond strength between the porcelain and composite resin luting cement. The article did contradict itself in saying that the abrasion technique has a lower strength level. Overall I am still confused at which technique this paper proved to be superior. The influence of cement lute, thermocycling and surface preparation on the strength of a porcelain laminate veneering material. Owen Addison, and Garry J. P. Fleming Dental Materials Volume 20, Issue 3 , March 2004, Pages 286-292
Aliya Elmajri <elma0014@umn.edu>
- Thursday, October 14, 2004 at 10:01:41 (CDT)

I read an article about dual cure cements and there use in fiber posts. They found that the strength was realted to the type of post used and the surfqac e treatment of the tooth structure. The bond strength was increased with the addition of silane agent."Microtensile bond strength of a dual-cure resin core material to glass and quartz fibre posts" Aksornmuang J, Foxton RM, Nakajima M, Tagami J. J Dent. 2004 Aug;32(6):443-50.
Chris McGrew <mcgr0181@umn.edu>
- Thursday, October 14, 2004 at 09:48:33 (CDT)

Dr. Perdigao talked about the advantage in the office of having a dual-cure resin cement(one that could set by light or on its own) because it was more versatile. The question then becomes, if you subscribe to a dual-cure resin cement, where do you use light cure, where do you use self cure and where do you use both? It was established in class that a thin veneer is best light cured and an all-ceramic crown is likely best self-cured. So, how about a porcelain inlay? The following study tested the three widely used dual-cure cements (RelyxArc, Calibra and Choice) and found that the self-cure feature was best used for class I porcelain inlays as oppposed to the dual-cure feature. This is explained by the amount of contraction stress that occurs as a result of photo-activation of these materials. The marginal leakage was also lower for the self-curing feature in all but the Calibra brand which showed no difference between microleakage in self-cure or dual-cure features.Braga RR, Ferracane JL, Condon JR.Polymerization contraction stress in dual-cure cements and its effect on interfacial integrity of bonded inlays.J Dent. 2002 Sep-Nov;30(7-8):333-40.
Gary Plotz <plot0010@umn.edu>
- Thursday, October 14, 2004 at 09:47:54 (CDT)

This study was done to evaluate the light transmission through porcelain veneers, to determine the degree of polymerization of the luting agent. The researchers used three light sources: conventional halogen, high intensity halogen, and plasma arc. They measured the light transmission through three thicknesses of Procera, as well as through 1mm thick disks of feldspathic porcelain, aluminous porcelain, and castable pressed ceramic. It was found that light intensity coupled with ceramic thickness dictated the amount of light transmission. Only the plasma arc and high intensity halogen generate enough intensity to polymerize the resin cement, and conventional halogen lights are insufficient to affect polymerization through veneers or all-ceramic crowns. Light transmission through all-ceramic dental materials. Rasetto, F. H., Driscoll, C. F., et.al. Journal of Prosthodontic Dentistry. 91(5): 441-6, 2004 May.
Elisabeth Warder <wilk0224@umn.edu>
- Thursday, October 14, 2004 at 09:36:22 (CDT)

In this article several aspects of cements are investigated. It is noted that mixing time and technique both affect the physical and mechanical properties of the cement. Next, it was highlighted that resin modified glass ionomers had the lowest score in terms of microleakage at the margins of restorations. Lastly, the use of resin modified glass ionomer cements in both anterior and posterior all ceramic restorations had low failure rates. Thus supporting the use of this agent in conjunction with all ceramic restorations. "Critical Appraisal." Demke, Richard. Ewoldsen, Nels Swift Jr., Edward J. Journal of Esthetic & Restorative Dentistry; 2002, Vol. 14 Issue 1, p49, 5p
Kristen Manolovits <olso1985@umn.edu>
- Thursday, October 14, 2004 at 07:44:27 (CDT)

I found todays lecture very interesting and informative. Choosing the type of cement to use in cementing porcelain restorations is important. There is a choice between light cure and dual cure cements depending on the type of restoration. This study looks at two different dual cure cements used with IPS Empress inlays. In this short term study, both the resin-modified glass ionomer cement and the chemical-cured resin composite cement functioned satisfactorily. Slight ditching was seen in the cements at the margins after two years, but none of the inlays failed. The researchers said that more long term research was needed and I agree. Clinical performance of pressed ceramic inlays luted with resin-modified glass ionomer and autopolymerizing resin composite cements. J Prosthet Dent. 1999 Nov;82(5):529-35. van Dijken JW, Ormin A, Olofsson AL.
Joshua Hiller <hill0672@umn.edu>
- Wednesday, October 13, 2004 at 22:11:15 (CDT)

Regarding luting cements mentioned in class; this study tried to assess the effects of sonic toothbrushes on commonly used permanent luting cements. The results showed differences between the tensile bond strengths of the three cements, but the differences were similar between the two groups: sonic and nonsonic toohbrush exposure. These findings suggest that the sonic toothbrush had no significant effect on the tensile bond strengths of any of the three tested luting cements. McDaniel TF, Browning WD, Dickinson G. Effects of sonic toothbrush use on permanent dental luting cements. Gen Dent. 2001; 49(1):90-3.
Steve Clifford <clif0047@umn.edu>
- Wednesday, October 13, 2004 at 21:00:38 (CDT)

After Dr. Perdigao's lecture discussing cementing and luting in operative dentistry, i decided to further research some of the different cements Dr. Perdigao discussed. I found an article discussing the color stability of different cements under porcelain veneers. The authors studied light cured, dual cured, and self cured cements in their study. They subjected the three cements (.3mm thickness) to accelerated aging equivalent to 900 hours on veneers .5mm in thickness. The veneers were then analyzed using spectrophotometry to determine chroma and hue changes. They found that the dual cure cement had the most chroma change time, and the self cure cement had the most hue change over time. The authors concluded that light cured resin cement is the best material for cementing porcelain laminate veneers. However, they cautioned that more research needed to be done in this realm. Hekimoglu C. Anil N. Etikan I. "Effect of accelerated aging on the color stability of cemented laminate veneers." International Journal of Prosthodontics. 13(1):29-33, 2000 Jan-Feb.
Brian Pelsue <pels0003@umn.edu>
- Wednesday, October 13, 2004 at 20:36:38 (CDT)

Today's lecture, given by Dr. Perdigao, focused on luting cements in dentistry. The choice of luting agent can vary for different restorative procedures, which demands a thorough understanding of the materials currently available. The article I reviewed studied adhesive luting of inderect dental restorations. Results indicated that resin-based composites are the material of choice for adhesive luting. Fine particle hybrid-type resin-based composites are superior to other agents in terms of material properties and wear behavior. "Adhesive luting of indirect restorations." American Journal of Dentistry. 13(Spec No):60D-76D, 2000 Nov.
Brandon Bussler <buss0099@tc.umn.edu>
- Wednesday, October 13, 2004 at 19:48:26 (CDT)

Because we may commonly use the dual-cured resin cements in the clinincs here at school, I decided to read a bit more about them. This study attempted to evaluate bonding compatibility between a dual-cured resin cement (in this case, Enforce), and several different adhesives (Prime & Bond, Scotchbond Multi Purpos, and the activator Self Cure). The authors found no apparent incompatibility between the various adhesives when used with this dual-cured resin cement. However, they recorded the lowest tensile bond strength when no light curing took place. Franco EB, Lopes LG, D'alpino PH, Pereira JC, Mondelli RF, Navarro MF. "Evaluation of compatibility between different types of adhesives and dual-cured resin cement." J Adhes Dent. 2002 Winter;4(4):271-5.
Tara Regenold <davi0497@umn.edu>
- Wednesday, October 13, 2004 at 19:40:55 (CDT)

After Dr. P's lecture today on resin cements, I was curious about the how well these resin cements cured beneath porcelain veneers. In this study, they researched the curing abilities of two different light sources on dual-curing resin cements beneath porcelain veneers. The two light sources tested were a halogen light and plasma arc light (PAL). They found that there was a significant difference in the curing efficiency, and that the halogen light produced better bond strength. My take-home from this is that although they are dual-curing cements, the light-cure aspect is important, and as dentists, we need to be aware of what type of curing we are doing so that we can provide the best restorations to our patients. Usumez A. Ozturk AN. Usumez S. Ozturk B. The efficiency of different light sources to polymerize resin cement beneath porcelain laminate veneers. Journal of Oral Rehabilitation. 31(2):160-5, 2004 Feb.
Carly Grothe <grot0072@umn.edu>
- Wednesday, October 13, 2004 at 17:53:55 (CDT)

I did my research on the hardness of dual-cured cements. This study investigated the flexural strength, flexural modulus and hardness of four proprietary resin cements. Materials tested were: Enforce and Variolink II (light-, self- and dual-cured), RelyX ARC (self- and dual-cured) and C & B (self-cured). RelyX ARC dual-cured showed higher flexural strength than the other groups. RelyX ARC and Variolink II depended upon photo-activation to achieve higher hardness values. Enforce showed similar hardness for dual- and self-curing modes. No correlation was found between flexural strength and hardness, indicating that other factors besides the degree of cure (e.g. filler content and monomer type) affect the flexural strength of composites. J Oral Rehabil. 2002 Mar;29(3):257-62.
Max Barsky <bars0040@umn.edu>
- Wednesday, October 13, 2004 at 17:41:33 (CDT)

The article I chose discussed microleakage of amalgam restorations of six different adhesive materials. Class V restorations (amalgam) were treated in extracted bovine teeth and Copalex was used as the control. Vitrebond had less leakage than any other material including Rely X (ARC), however there is a greater incidence of solubility with Rely X over time. Rely X (ARC) demonstrated good adhesion to dentin and enamel and had low microleakage scores. It also has "demonstrated ability to preven leakage in Class V cavities". The aritcle indicated that bonded amalgam restorations are indicated for cavity wall reinforcement and for cusp reinforcement. "Microleakage in bonded amalgam restorations using different adhesive materials" Maximiliano Sergio Cenci, Evandro Piva et al. Braz. Dent. J. v.15 .1 Riverirao Preto 2004.
Robin Donnelly <donn0086@umn.edu>
Minneapolis, MN USA - Wednesday, October 13, 2004 at 17:23:53 (CDT)

With all the choices in light cure resin cements, I was wondering about which type of light source would be the most effective. The article "Influence of different light sources on microtensile bond strength and gap formation of resin cement under porcelain inlay restorations" authored by Ozturk AN and Usumez A. found in J Oral Rehabil. 2004 Sep;31(9):905-10 studies the efficiency of different light sources on microtensile bond strength and the gap formation of resin cement. The different light source were conventional halogen light and a plasma arc unit This studie showed that samples polymerized with a halogen light produced better microtensile bond strength than the plasma unit.
Emma Otis <otis0025@umn.edu>
- Wednesday, October 13, 2004 at 16:17:57 (CDT)

This particular article was based on the use of light cured polymerization cememtation of laminate veneers. Within the limitations of this study, the intensity of light transmitted through ceramic veneers was dictated by the polymerization unit and the type and thickness of the ceramic. With conventional halogen polymerization units, there may be insufficient light transmission through thicker veneers or all-ceramic crowns for adequate light polymerization. So, in conclusion it might be a wise idea to use a self-curing luting cements.
Mike Hom <homx0008>
- Wednesday, October 13, 2004 at 16:04:34 (CDT)

this study compaired the cureing ability of a Halogen light system vs. the new plasma arc light units. The study found that the PAC system produced a significantly weaker bond than that of the Halogen system when used in conjunction with a dual cure cement to bond ceramic veneers. J Oral Rehabil. 2004 Feb;31(2):160-5 The efficiency of different light sources to polymerize resin cement beneath porcelain laminate veneers. Usumez A, Ozturk AN, Usumez S, Ozturk B.
Jeff Moos <moos0021@umn.edu>
- Wednesday, October 13, 2004 at 15:51:06 (CDT)

My article was a 10 year evaluation of CAD/CAM ceramic inlays cemented with two different types of cements. Each patient had an inlay luted with dual cured resin composite and one luted with a chemically cured resin composite. After 10 years, 89% of the inlays still functioned well. All the inlays that had to be redone were luted with the dual cured resin composite. They concluded that the properties of the luting agents seem to affect the longevity of the type of ceramic inlays evaluated. (Sjogren G, Molin M, van Dijken JW. A 10-year prospective evaluation of CAD/CAM-manufactured (Cerec) ceramic inlays cemented with a chemically cured or dual-cured resin composite. Int J Prosthodont. 2004 Mar-Apr;17(2):241-6)
Jackie Jensen <jens0657@umn.edu>
- Wednesday, October 13, 2004 at 15:45:31 (CDT)

Abraded cemented veneers were found to have a significantly higher mean fracture strength than acid-etched/composite resin glued porcelin veneers. Therefore etching porcelin provides mechanical interlocking, and composite resin polymerization shrinkage strengthens porcelain by compressive stresses on the porcelain surface, but acid etching also has a weakening effect on the porcelain veneer surface. Addison O. Fleming GJ. The influence of cement lute, thermocycling and surface preparation on the strength of a porcelain laminate veneering material. Dental Materials. 20(3):286-92, 2004 Mar.
Aimee Potasek <pota0013@umn.edu>
- Wednesday, October 13, 2004 at 14:44:51 (CDT)

When cementing your fiber post, you may want to consider using a dual-cured resin cement. This paper discussed the microtensile bond strength between fiber posts and dual-cured resin cements. They found that the bond strength depends on the type of post used and the surface treatment performed. Silica-zirconium glass fiber posts and quartz fiber posts were used in the study. Each had their surface treated by one of the four following ways: a dual-cure bonding agent only, a dual-cure bonding agent along with light curing, a silane coupling bonding agent only, or a silane coupling bonding agent along with light curing. The researchers concluded that use of a silane coupling agent improved the bond strength of the dual-cure resin material to the silica-based fiber posts. They also found that light curing of the bonding agent to the post surface had an effect on the bond strength. Finally, there was no difference in the bond strengths between the upper, middle, and bottom regions of the post (which is suprising considering they were light cured from the top of the tooth). (Aksornmuang, J., Foxton, R., Nakajima, M., and J. Tagami. "Microtensile bond strength of a dual-cure resin core material to glass and quartz fiber posts." Journal of Dentistry. (2004) 32, 443-450.)
Sarah A Nelson <nels2267@umn.edu>
- Wednesday, October 13, 2004 at 14:39:04 (CDT)

Spohr et al. (2003) compared the in vitro tensile bond strengths resulting from different ceramic surface treatments of IPS Empress 2 ceramic framework and Rely X adhesive resin cement. The different ceramic surface treatments included hydrofluoric acid etching and sandblasting, both with and without the application of a silane coupling agent. They found that the silane coupling agent resulted in improved bond strength over the groups in which silane was not used. They found that the most effective surface treatment was etching with 10% hydrofluoric acid, both with and without silane application. They concluded that the best ceramic restoration surface treatment was the combined application of 10% hydrofluoric acid and silane, echoing, in-part, Dr. Perdigao's discussion today. Spohr AM, Sobrinho LC, Consani S, Sinhoreti MA, Knowles JC. Influence of surface conditions and silane agent on the bond of resin to IPS Empress 2 ceramic. Int J Prosthodont. 2003; 16(3):277-82. Keyword: Rely-x
Lipschultz, Joshua G. <lips0033@umn.edu>
- Wednesday, October 13, 2004 at 14:37:29 (CDT)

In class today we discussed light-cured resin cements and their wide use in porcelain veneers. The study that I reviewed measured the spectral transmittance of porcelain laminate veneers at three different thicknesses (0.50, 0.75, and 1 mm) and three different opacities (25%, 75%, and 100%). The transmittance values that were obtained were then used to estimate the setting times for different light-cured cements for porcelain veneers. The results demonstrated that the thickness of the porcelain veneer was the primary factor affecting light transmission instead of the opacity. J Prosthet Dent. 1991 Oct;66(4):434-8
Marianna Elimelakh <elim0001@tc.umn.edu>
- Wednesday, October 13, 2004 at 14:37:09 (CDT)

Today we discussed the relative importance in luting cements and the steps to accomplish cementation. I was interested in seeing if the length of etching time had an impact on the final outsome of the restoration. The article I found researched "repair bond strength of a laboratory processed composite treated with hydrofluoric acid gels of different acid concentrations and for various etching times and repaired with a flowable composite. There were no differences in the repair bond strengths with respect to the three different acid concentrations or the five etching times tested. The minimum etching time to observe an etched pattern was at 60 seconds with the highest concentration of hydrofluoric acid (9.5%)." Trajtenberg CP. Powers JM. Effect of hydrofluoric acid on repair bond strength of a laboratory composite. American Journal of Dentistry. 17(3):173-6, 2004 Jun.
Whitney Hustad <hust0040@umn.edu>
- Wednesday, October 13, 2004 at 14:36:31 (CDT)

The article I found explored the marginal integrity of all ceramic MOD inlay restorations after luting. The study involved several different kinds of luting agents, including resin, resin-modified glass ionomer, and compomer. The study found that resin cements performed the best, achieving over 90% marginal integrity after thermal cycling and loading. In addition, researchers actually saw an increase in the 100% integrity samples of the dentin-restoration interface luted with Panavia, a resin cement that is available to use here in clinic. The study also found that resin-modified glass ionomers performed at 55-80% marginal integrity, and compomers performed poorly, achieving less than 20% marginal integrity. The authors note that there are some special situations that would indicate these materials as luting agents. Martin Rosentritt, , Michael Behr, Reinhold Lang and Gerhard Handel. Influence of cement type on the marginal adaptation of all-ceramic MOD inlays. Dental Materials Volume 20, Issue 5 , June 2004, Pages 463-469
Liz Martin <mart1185@umn.edu>
- Wednesday, October 13, 2004 at 13:34:50 (CDT)

The authors of this study wanted to investigate the influence of the different polymerization types of three dual-cured resin luting agents (Panavia Fluoro Cement, Clapearl DC, and Vita Cerec Duo Cement) and two chemically cured luting agents (Panavia 21 and Super-Bond C&B) on the early bond strengths and durability of the bond to Cerec 2 ceramic material. Shear bond strength test were performed at 10 and 20 minute intervals, and the authors report that the two chemically-cured resin luting agents showed significantly lower bond strengths than the three dual-cured resin luting agents. Early bond strength and durability of bond between a ceramic material and chemically-cured or dual-cured resin luting agent. Am J Dent. 2001 Apr; 14(2):85-8.
Joey Petrino <petr0212@umn.edu>
- Wednesday, October 13, 2004 at 13:31:48 (CDT)

The study I looked at evaluted the hardness of dual-cured resin cements after curing with different types of lights or by self-cure. The study used samples from four different kinds of resin cements, Variolink II, Calibra, Nexus 2 and RelyX ARC. Each sample was cured with a halogen light or LED for varying amounts of time (10, 30 or 40 seconds). The samples were only cured from the top of the sample in order to evaluate depth of cure. Additional samples were self-cured for varying increments of time (15, 30 and 60 minutes and 24 hours). Results showed that in every case of self-cure alone the hardness was less than that of the light-cured samples. High intensity halogen light cure resulted in the most hardness, and LED resulted in the lowest hardness. [Hardening of dual-cure resin cements and a resin composite restorative cured with QTH and LED curing units. Journal (Canadian Dental Association). 70(5):323-8, 2004 May]
Stacey Vogt <vogt0056@umn.edu>
- Wednesday, October 13, 2004 at 13:30:57 (CDT)

Todays lecture helped in clear up some lingering questions about luting agents, specifically looking at the composite resin cements. In the paper,Comparison of bond strength between a conventional resin adhesive and a resin-modified glass ionomer adhesive: an in vitro and in vivo study;Am J Orthod Dentofacial Orthop. 2004 Aug;126(2):200-6; quiz 254-5, the researchers performed both in vitro and in vivo analysis of two cements,Fuji Ortho LC(resin modified glass ionomer adhesive) and Light Bond(conventional resin adhesive). No difference was found between the two cements when comparing the in vivo survival rate of orthodontic brackets between the 2 adhesives. Since very little in vivo data exist for these materials it is difficult to extrapolate the in vitro data in the decision making of real life cases. Unfortunately, it appears that clinical experiance will continue to determine the choice of luting agent used for many practicing dentists until sufficiant time has elapsed with these newer materials to design valid in vivo studies with respectable results.
Chris Sampair <samp0106@umn.edu>
- Wednesday, October 13, 2004 at 13:29:22 (CDT)

Cement remaining after the removal of the provisional can impair the etching quality of the tooth surface and the fit and final bonding of the porcelain veneer. I found a study that looks at residual material left by three different cementing methods: Temporary eugenol-free cement, spot etching combined wiht dual-curing luting cement and polyurethane adhesive combined with dual-curing luting agent . The study concluded that the use of polyurethane adhesive combined with dual-curing cement revealed significantly less teeth with debris than the other methods. Dumfahrt H, Gobel G. Bonding Porcelain Laminate Veneer Provisional Restorations: An experimental Study. J. of Pros Dent. 82(3):281-5, 1999 Sept.
Jill Biles <bile0009@tc.umn.edu>
- Wednesday, October 13, 2004 at 12:45:36 (CDT)

I found this article: "The influence of cement lute, thermocycling and surface preparation on the strength of a porcelain laminate veneering material." Dent Mater. 2004 Mar;20(3):286-92. The article's purpose was to investigate the effect of thermocycling on the development of surface flaws on the cemented surfaces of Porcelin laminate veneer restorations prepared by acid-etching or alumina abrasion. They state that composite resin polymerisation shrinkage may help to strengthen porcelain surfaces by imposing a compressive stress on the porcelain surface. However, the strength of the acid etched cemented groups when bonded to composite resin were weaker than the abraded specimens. Etching the porcelain does not only provide the necessary surface roughness for mechanical retention but appears to have a weakening effect on the porcelain surfaces. I found this to be intersting after what was presented today in lecture.
Duane Van Nieuwenhuyzen <vann0086@umn.edu>
- Wednesday, October 13, 2004 at 12:04:51 (CDT)

When using a cement to bond a veneer to tooth structure there are two interfaces formed the resin to the etched porclain and the resin to the tooth. This study analyzed the structure of the two interfaces to try and find an explanation for some of the shortcomings of bonded porcelain veneers. They found that the luting composite interlockes into the retentive etch pits of both the porcelain and tooth substrates, which contributes to strong adhesion of porcelain veneers with good retention. It also suggests that a multi-step total-etch adhesive system can increase the amount of adhesion even to the less retentive cervical enamel and exposed dentin. Porcelain veneers bonded to tooth structure: an ultra-morphological FE-SEM examination of the adhesive interface. Dent Mater. 1999 Mar;15(2):105-19
Marjorie Voelker <voel0020@umn.edu>
- Wednesday, October 13, 2004 at 11:46:01 (CDT)

After Dr. Perdigo's lecture about dual cure cements, I was just curious about how effective is the adhesive used with dual cure cements. I found a study that was conducted to test the compatibility of adhesive and dual cure cements. The study used prime and bond NT, scotchbond multi-purpose, One-step and Single bond. The cements that were used are Rely X ARC and enforce. Shear strenght was tested after 48 hours of storage of preped, and cemented teeth at 37 degrees, to evaluate the compatibility for self cure mode and dual cure mode. The study concluded that Scotchnond Multi-purpose Plus was the only adhesive to present similar results in term of bond strength when associated with cements in dual and self cure mode. Other adhesives ranged from 33 - 76% in bond strength between dual and self cure modes. Compatibility of dental adhesives and dual cure cements. Am J Dent. 2003 Aug; 16 (4): 235-8.
Rachana Patel <pate0108@umn.edu>
- Wednesday, October 13, 2004 at 11:42:41 (CDT)

Resin cements have advantages over conventional luting cement, by having the ability to bond to both the tooth structure and the restoration. In this article, the authors evaluated the marginal integrity of all-ceramic MOD preparations luted to human molars using resin cement, resin modified glass-ionomer cement, and a compomer cement after thermal cycling and mechanical loading. The results from this study indicated that resin cement performed better than resin glass-ionomer cement and compomer in marginal adaptation. Thus, to optimize the longevity of your all-ceramic restoration, the use of resin cement is superior in marginal adaptation. Reference: Rosentritt M, Behr M, Lang R, Handel G. Influence of cement type on the marginal adaptation of all-ceramic MOD inlays. Dent Mater. 2004; 20(5): 463-9.
Anh Kov <vuon0016@umn.edu>
- Wednesday, October 13, 2004 at 11:37:50 (CDT)

From Dr. Perdiagao lecture on luting and cementing agents with porcelain, I read a study comparing the shear bond strength of porcelain under different technique and with/without coupling agents. The study was an invitro test in which 36 ceramic plates of six plates in each of the six groups were used to test the bonding strength. The two groups compared different techniques with an adhesive system with and without silane. The 6 different techniques were sandblasting the ceramic only, polishing the ceramic plates, using HF as an acid etch for 5 s or 60 s and using H3PO4 for 5 s or 60 s. The bond strength was measured using a micro-shear bond test apparatus and analyzed with SEM. The two main results were: 1) A silane coupling agent mixed with an acidic primer can effectively increase the bonding strength between resin cement and cast glass ceramics. 2)Olympas glass ceramics surfaces etched by hydrofluoric acid were found to provide no greater bond to resin cement than mechanical roughening with a sandblast. Another result that seems worth noting is that the longer the ceramic was etched (60 s) the resulting bond strength appears to decrease vs. 5 s which makes me wonder then if Dr. Perdigao's technique for etching HF for 2 min. in lab compromises bond strength per this study. [Yasushi Shimada, Saori Yamaguchi and Junji Tagami. Micro-shear bond strength of dual-cured resin cement to glass ceramics. Dental Materials Vol. 18(5), July 2002: 380-388]
Adam Beers <beer0033@umn.edu>
- Wednesday, October 13, 2004 at 11:37:10 (CDT)

"A prospective ten-year clinical trial of porcelain veneers." Peuman M, De Munck J Fieuws S. J Adhes Dent. 2004 Spring,6(1):65-76. After a very interesitng and informative lecture this morning I wanted to get a little more info on Veneers. How long can we expect something so fragile to last. Well in the paper that I read the authors place 87 maxillary anterior teeth in 25 patients. They recalled these patients after five years and all were present, then again at ten and 93% of the restorations were still present. They also looked at esthetics, marginal integrity, retention, cliical microleakage, caries recurrence, fracture , vitality, and patient satisfaction. All the veneers maintained their esthetic appaerance after 10 years of clinical service. Of the 28% of the veneers that had clinicall unacceptable problem were repairable. Therefore I think it would be safe to say porcelain veneers represent a reliable, effective procedure for conservative treatment of unesthetic anterior teeth.
Charles Duchsherer <duch0041@umn.edu>
- Wednesday, October 13, 2004 at 11:35:31 (CDT)

After the lecture, I looked further into porcelain cements. The article I read looked at what type of cement should be used for each particular type of restoration (ceramic vs gold). The results were "these newer cements have specific clinical applications, they should not be routinely used for the cementation of metal castings because they are clearly more technique-sensitive than traditional luting agents. Zinc-phosphate cement remains the cement of choice for cementing cast gold and metal-ceramic restorations." The author also concluded "that these improved physical properties do not necessarily result in improved clinical performance." This means the clinician must be wary of new cements and that she must use the cements according to the manufacturer's directions. Donovan TE, Cho GC.Contemporary evaluation of dental cements.Compend Contin Educ Dent. 1999 Mar;20(3):197-9, 202-8, 210 passim; quiz 220.
Breynne Fordahl <ford0107@umn.edu>
- Wednesday, October 13, 2004 at 11:32:16 (CDT)

I found the article "Clinical and scanning electron microscopic assessments of porcelain and ceromer resin veneers." The article talks about ceromer resin and compares it with the standard porcelain veneers looking at esthetic quality and surface finish. The study showed that the standard porcelain veneers proved to be a much better material than the new ceromer resin veneers. The ceromer resin showed a poor surface finish and had discolorization at the margins. It seems as though the old standardof porcelain turned out to be the best in this case Citation:Indian J Dent Res. 2003 Oct-Dec;14(4):264-78.
Justin Hagen <hage0449@umn.edu>
- Wednesday, October 13, 2004 at 11:31:55 (CDT)

Today we discussed dual-cured resin cements. The article I found looked at three cements: Choice, RelyX ARC, and Calibra. These were tested in the presence or absence of photo-activation, therefore, in either a dual-cure or a self-cure mode. The goal was to determine the difference in contraction stress of these two modes; this stress could lead to marginal leakage and gap formation. Stress developed in the dual-cure mode higher than self-cure for all three cements. Choice and RelyX ARC showed higher microleakage in dual-cure mode, whereas Calibra showed no difference. Contraction gap formation also showed no significant difference in any of the three cements. The higher stress generated in dual-cure cements subjected to photo-activation led to higher marginal leakage. If the photo-activation creates a problem, it would cause practitioners to question the use of light-cured resin cements for veneers and dual-cured resin cements for the bonding of other restorations. Obviously, however, there are other advantages of these products that lead to their continued use. Braga, Roberto, Ferracane, Jack and Condon, John. Polymerization contraction stress in dual-cure cements and its effect on interfacial integrity of bonded inlays. Journal of Dentistry. Volume 30, Issue 7-8, Sept-Nov 2002;333-340.
Christy Bulman <holu0021@umn.edu>
- Wednesday, October 13, 2004 at 10:12:23 (CDT)

This study looked into the effect of surface roughness on the strength of veneer ceramics. The strength of a ceramic restorations depend of how rough the veneering porcelain. The researchers were studying the roughnesses below a critical microscopic defect size that will also affect flexural strength. The failure stresses were evaluated on 4 veneer ceramics with 4 different surface roughnesses. It was determined that the final preparation of a ceramic restoration was critical to the strength of the material. It was also determined that ceramic veneering materials can be compared more objectively with respect to their strength by means of roughness-free strength values. Since esthetic dentistry and veneers are more popular, knowing how much flexural strength can affect the longevity of the restoration. H. Fischer, M. Schäfer, and R. Marx. Effect of Surface Roughness on Flexural Strength of Veneer Ceramics J Dent Res 82(12): 972-975, 2003
Chia-Yin Lo <loxx0048@umn.edu>
- Wednesday, October 13, 2004 at 10:11:57 (CDT)

The study I read for this lecture compared nine different flowable composites to luting cements for porcelain veneers. They were tested at three different forces that simulate the force used to seat the veneer in the mouth. They found that at the lightest force that 8 out of the 9 composites tested as well as the control luting cement. At the hardest force level, though, only 2 out of the 9 tested as well as the luting cement. They concluded that when using flowable composite with porcelaine veneers that light to moderate force be used when seating the veneer to get the maximum result. Moon PC. Tabassian MS. Culbreath TE. Flow characteristics and film thickness of flowable resin composites. Operative Dentistry. 27(3):248-53, 2002 May-Jun.
Jessica Allison <alli0086@umn.edu>
- Wednesday, October 13, 2004 at 09:44:07 (CDT)

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